doc: spell fix.

[bison.git] / NEWS

diff --git a/NEWS b/NEWS
index 989e6b8b234db8748a5fc5a46b9a9958eb11c90d..293e2dfda6a20e13191d58702d220fa313f77bcb 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -24,6 +24,15 @@ Bison News
   Also, it is possible to add code to the parser's constructors using
   "%code init" and "%define init_throws".
 
+** C++ skeleton improvements
+
+  The C++ parser features a syntax_error exception, which can be
+  thrown from the scanner or from user rules to raise syntax errors.
+  This facilitates reporting errors caught in sub-functions (e.g.,
+  rejecting too large integral literals from a conversion function
+  used by the scanner, or rejecting invalid combinations from a
+  factory invoked by the user actions).
+
 ** Variable api.tokens.prefix
 
   The variable api.tokens.prefix changes the way tokens are identified in
@@ -60,7 +69,15 @@ Bison News
   allow the programmer to prune possible parses based on the values of
   runtime expressions.
 
-* Changes in version 2.5 (????-??-??):
+* Changes in version 2.5.1 (????-??-??):
+
+** Some portability problems in the test suite have been fixed.
+
+** Minor improvements have been made to the manual.
+
+** YYBACKUP works as expected.
+
+* Changes in version 2.5 (2011-05-14):
 
 ** Grammar symbol names can now contain non-initial dashes:
 
@@ -393,7 +410,7 @@ Bison News
 
     bison -Werror,none,yacc gram.y
 
-*** The `none' category now disables all Bison warnings.
+*** The `none' category now disables all Bison warnings:
 
   Previously, the `none' category disabled only Bison warnings for
   which there existed a specific -W/--warning category.  However,
@@ -402,6 +419,16 @@ Bison News
 
     bison -Wnone gram.y
 
+** Precedence directives can now assign token number 0:
+
+  Since Bison 2.3b, which restored the ability of precedence
+  directives to assign token numbers, doing so for token number 0 has
+  produced an assertion failure.  For example:
+
+    %left END 0
+
+  This bug has been fixed.
+
 * Changes in version 2.4.3 (2010-08-05):
 
 ** Bison now obeys -Werror and --warnings=error for warnings about
@@ -880,26 +907,26 @@ Bison News
   if the symbols have destructors.  For instance:
 
      exp: exp "?" exp ":" exp { $1 ? $1 : $3; }
-       | exp "+" exp
-       ;
+        | exp "+" exp
+        ;
 
   will trigger a warning about $$ and $5 in the first rule, and $3 in
   the second ($1 is copied to $$ by the default rule).  This example
   most likely contains three errors, and could be rewritten as:
 
      exp: exp "?" exp ":" exp
-           { $$ = $1 ? $3 : $5; free ($1 ? $5 : $3); free ($1); }
-       | exp "+" exp
-           { $$ = $1 ? $1 : $3; if ($1) free ($3); }
-       ;
+            { $$ = $1 ? $3 : $5; free ($1 ? $5 : $3); free ($1); }
+        | exp "+" exp
+            { $$ = $1 ? $1 : $3; if ($1) free ($3); }
+        ;
 
   However, if the original actions were really intended, memory leaks
   and all, the warnings can be suppressed by letting Bison believe the
   values are used, e.g.:
 
      exp: exp "?" exp ":" exp { $1 ? $1 : $3; (void) ($$, $5); }
-       | exp "+" exp         { $$ = $1; (void) $3; }
-       ;
+        | exp "+" exp         { $$ = $1; (void) $3; }
+        ;
 
   If there are mid-rule actions, the warning is issued if no action
   uses it.  The following triggers no warning: $1 and $3 are used.
@@ -1143,16 +1170,16 @@ Bison News
   In agreement with POSIX and with other Yaccs, leaving a default
   action is valid when $$ is untyped, and $1 typed:
 
-       untyped: ... typed;
+        untyped: ... typed;
 
   but the converse remains an error:
 
-       typed: ... untyped;
+        typed: ... untyped;
 
 ** Values of mid-rule actions
   The following code:
 
-       foo: { ... } { $$ = $1; } ...
+        foo: { ... } { $$ = $1; } ...
 
   was incorrectly rejected: $1 is defined in the second mid-rule
   action, and is equal to the $$ of the first mid-rule action.
@@ -1563,7 +1590,7 @@ End:
 
 -----
 
-Copyright (C) 1995-2011 Free Software Foundation, Inc.
+Copyright (C) 1995-2012 Free Software Foundation, Inc.
 
 This file is part of Bison, the GNU Parser Generator.